A  May  11,  1907. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 


BUREAU  OF  ANIMAL  INDUSTRY.— Bulletin  No.  09. 

A.  D.  MELVIN,  Chief  op  Bumau. 


— 

— 


THE  DANGER  FROM  TUBERCLE  BACILLI 
IN  THE  ENVIRONMENT  OF  TUBER- 
CULOUS CATTLE. 


BY 


E.  C.  SCHROEDER,  M.  D.  V., 

Superintendent  of  Experiment  Station, 
AND 

W.  E.  COTTON, 

Expert  Assistant  at  Experiment  Station 


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WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 

1907. 


Issued  May  11,  1907. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.— Bulletin  No.  99. 

A.  D.  MELV1N,  Chief  of  Bureau. 


THE  DANGER  FROM  TUBERCLE  BACILLI 
IN  THE  ENVIRONMENT  OF  TUBER- 
CULOUS CATTLE. 


BY 
E.  C  SCHROEDER,  M.  D.  V., 

Superintendent  of  Experiment  Station, 
AND 

W.  E.  COTTON, 

Expert  Assistant  at  Experiment  Station 


WASHINGTON: 

GOVERNMENT    PRINTING   OFFICE. 

1907. 


BUREAU  OF  ANIMAL  INDUSTRY. 


Clii>f:   A.  I>.  Mn\i.\. 

Assintant  Chief:   A.  M.  1\\i:ki  m.ton. 

Chief  Clerk:  v..  B.  Jama 

llinvhcmii-  Dirixinti:   M.   I>okski.  « - 1 1  i « - 1" ;   .Iamks  A.    Kmkky,  :issist;int   <liicf. 
Unit  u  IHrisimi:   Da  II.  Wkhstkii,  chief :    ( '.  15.  Lank,  assistant  chief. 
hi.<<i>rttit,)i    Itiriximi:     Bid     P.    SiuiixtM,    chief;      Muiuu.s     WOOHX,    HWWWfft 
chief. 

PcfAolOffeoJ     IHrixiaii:    John     It.    Mihii.kk.    chief;    Henry    J.     Wahiihubn, 

nit  chief. 
Qiiamntim   IHrisimi:   Hiciiakh  \V.  Hickman,  chief. 
IHrision  <,f  ZOQ&ogVi  B.  II.  Ransom,  chief. 
Animal  II  us  ha  ml  man :   QUOMI  -M.  Kommel. 
Kilitnr:   .Iamks  If.  I'kkkw 
Librarian:   Hkatkm k  ohkki.y  Kouebs. 

1  M'KRIMKNT  STATION. 

Sii/h  rinti  nth nl :    ]■'..  < '.  S>  iirokkkb. 
/.'//<«;/    [ssistnnt:    W.  E.  OOTItNI. 
2 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Animal  Industry, 
Washington,  D.  6".,  April  4,  1907. 
Sir:  I  have  the  hon6r  to  transmit  herewith,  and  to  recommend 
for  publication  as  Bulletin  No.  99  of  this  Bureau,  an  article  entitled 
"  The  Danger  from  Tubercle  Bacilli  in  the  Environment  of  Tuber- 
culous Cattle,"  by  Dr.  E.  C.  Schroeder  and  W.  E.  Cotton,  of  the 
Bureau  Experiment  Station. 

The  investigations  with  which  the  article  deals  show  that  tuber- 
culous cattle,  before  they  lose  their  general  appearance  of  health, 
often  pass  feces  heavily  infected  with  tubercle  bacilli,  and  that  the 
same  is  true  of  healthy  cattle  that  are  permitted  to  swallow  tubercle 
bacilli  in  their  feed  or  in  their  drinking  water.  When  test  animals 
are  inoculated  with  such  feces,  or  with  milk  soiled  with  such  feces, 
they  commonly  become  affected  with  tuberculosis. 

The  work  as  a  whole  shows  that  the  general  condition  or  appear- 
ance of  a  tuberculous  animal  gives  no  indication  as  to  the  time  when 
it  will  begin  to  distribute  tubercle  bacilli  #nd  become  dangerous; 
that  the  milk  from  all  tuberculous  cattle,  irrespective  of  the  condi- 
tion of  their  udders,  should  be  regarded  as  dangerous,  and  that  even 
the  milk  of  healthy  cows  if  it  is  drawn  in  the  environment  of  tuber- 
culous cattle  may  contain  tubercle  bacilli. 

Since  the  tuberculin  test  is  the  only  practical  means  of  detecting 
tuberculosis  in  the  live  animal  before  an  advanced  stage  is  reached, 
the  importance  of  testing  dairy  cows  with  tuberculin  and  removing 
every  reacting  animal  is  again  emphasized. 

Respectfully,  A.  D.  Melvin, 

Chief  of  Bureau. 
Hon.  James  Wilson, 

Secretary  of  Agriculture. 

3 


CONTENTS. 


Page. 

Introduction 7 

Description  of  cattle  used  in  experiments 8 

Examination  of  feces  for  tubercle  bacilli 8 

Microscopic  examinations 8 

Inoculation  tests  with  guinea  pigs 9 

Summary  of  feces  examinations 11 

Tests  of  saliva,  nasal  discbarge,  urine,  and  milk 11 

Feces  in  milk  the  real  danger  from  tuberculous  cattle 13 

Persons  probably  contract  tuberculosis  chiefly  by  ingestion IT 

Infectiousness  of  soiled  milk  shown  by  inoculation  of  guinea  pigs 18 

Additional  feeding  and  inoculation  tests 21 

Conclusions 22 

5 


Digitized  by  the  Internet  Archive 

in  2007  with  funding  from 

Microsoft  Corporation 


http://www.archive.org/details/dangerfromtubercOOschriala 


THE  DANGER  FROM  TUBERCLE   BACILLI   IN  THE  ENVIRONMENT 
OF  TUBERCULOUS  CATTLE. 


INTRODUCTION. 

The  manner  in  which  tubercle  bacilli  are  thrown  out  by  and  reach 
the  environment  of  persons  affected  with  tuberculosis  has  been  care- 
fully studied ;  consequently,  we  know  with  practical  certainty  that  all 
cases  of  human  tuberculosis  may  be  divided  into  two  classes — "  open," 
or  dangerous,  and  "  closed,"  or  less  dangerous.  A  "  closed  "  may  at 
any  time  become  an  "  open  "  tuberculosis,  but  it  is  from  the  latter 
only,  which  includes  all  persons  whose  lungs,  air  passages  and  im- 
mediately related  structures  are  affected,  that  tubercule  bacjlli  are 
disseminated  in  a  way  dangerous  to  health.  This  is  the  view  sanc- 
tioned b}'  Dr.  Robert  Koch  in  his  "  Nobel  lecture,"  delivered  at 
Stockholm  on  December  10,  1905.° 

Concerning  tuberculous  animals  our  knowledge  is  not  so  definite, 
but  it  is  of  the  highest  importance  that  we  should  know  how  tubercle 
bacilli  are  scattered  by  them,  too,  not  that  we  may  establish  an 
"  open  "  and  a  "  closed  "  class,  but  to  enable  us  to  know  how  we  can 
best  prevent  the  transmission  of  tuberculosis  from  animal  to  animal 
and  from  animal  to  man. 

Many  prominent  investigators  are  convinced  that  tuberculosis  of 
animals  constitutes  a  serious  danger  for  man;  others  are  not;  but 
all  agree  that  it  is  an  occasional  danger,  more  frequently  for  children, 
whose  diet  consists  largely  of  milk,  than  for  adults.  While  this  mat- 
ter awaits  a  solution  and  there  is  not  perfect  harmony  among  au- 
thorities, we  may  reasonably  assume  that  it  is  better  to  guard  against 
exposure  to  infectious  material  scattered  by  persons  and  animals  than 
only  against  that  scattered  by  persons.  Protective  measures  that 
take  into  account  the  clearly  defined  menace  and  neglect  the  highly 
probable  danger  are  insufficient,  especially  when  the  probable  danger 
is,  as  in  this  case,  believed  to  be  actual  by  many  men  who  are  compe- 
tent to  judge. 

Hut  even  if  persons  are  eventually  shown  to  be  comparatively  safe 
against  infection  from  tuberculous  animals,  the  manner  of  dissemina- 
tion  is  nevertheless  an  important  economic  problem,  because  animals 
have  been  repeatedly  shown  to  l)e  more  susceptible  to  tuberculous  in- 

«  Translation  in  the  Lancet  of  M.-iy  28,   l'.HXi. 


8  DAN<. I  l:    I  ROM     I  i   BEN  ULOU8    I   \  I  I  r  I  . 

feet  ion  from  animals  llian  from  num.  ami  tuberonlOBfl  among  animal- 
is.  tram  the  stock  owners  point  of  new,  one  of  the  rerj  sorioui  oon 
ditJone  with  which  the  animal  industry  bu  to  deaL 
In  this  irtiok  tie  recorded  some  ubestvationa  <>n  the  tubercle 

liacilli  expelled  l»\    cattle  ami  an  :it  t  <in  |  >l    i-  made  l<»  -how    how    these 

bacilli  may  Ik*  scattered  and  become  I  great  dinger  t<>  animal-,  and, 
■a  ire  believe,  also  to  man. 

DESCRIPTION  OF  CATTLE   USED   IN   EXPERIMENTS. 

The  cattle  from  which  the  material  area  obtained  for  the  observe- 
tiona  require  the  following  short  description: 

Cow  No.  l  has  been  effected  with  tuberculosis  for  several  yean. 
Aside  from  a  tuberculin  teat,  which  showed  her  t«>  be  tuberculous, 

there  is  nothing  in  her  condition  that   would  condemn  her  for  08 
a  dairy  cow. 

Cow  No.  LIS  is  affected  with  advanced  tuberculosis.  She  is  -till 
alive,  quite  thin,  and  ha-  a  severe  and  frequent  cough. 

Cows.  Nos.  M.  :'.7I.  and  HM  are  three  healthv  animal-  that  were 
fed  a  small  amount  of  culture  of  tubercle  bacilu  daily  in  their  drink- 
ing water  during  the  time  the  observations  were  in  progress. 

Cow  No.  l\'2?>  and  steer  No.  .">•_".»  are  two  CaSCS  0$  recent  tuberculosUj 
they  are  living,  and  the  knowledge  that  they  are  tuberculous  i-  baaed 
entirely  on  a  tuberculin  test 

Cow  No.  372  was  found  on  autopsy  to  have  a  tuberculous  affection 
limited  to  one  post  -pharyngeal  Lymph  gland. 

Cow  No.  373  was  found  on  autopsy  t<>  be  affected  with  tuberculosis 
of  the  lung  and  liver  and  the  mediastinal,  portal,  and  mesenteric 
lymph  gland--.    The  lesions  were  widely  scattered,  l>ut  not  extensive. 

Cow  No.  I7«'.  ia  living.  IS  in  good  condition,  and  was  aged  until 
recently,  and  would  1m>  in  use  now,  a-  a  private  family  cow,  if  a 
tuberculin  test  had  not  shown  that  she  is  affected  with  tuberculosis. 

EXAMINATION  OF  FECES   FOR  TUBERCLE  BACILLI. 

■ncnoaoogp    n \ win  itsohs, 

Small  portions  of  feces,  taken  at  random  from  the  interior  of 
masses  freshly  passed  l»y  the  cattle,  were  smeared  00  thin  squares  of 
glass,  which  are  generally  known  in  connection  with  microscopic 
work  as  (over-glHsses.  Similar  preparations  were  made  with 
material  gently  BCTaped  fn»in  the  mUCOUS  surface,  jn-t  inside  the 
anal  orifice,  of  the  rectum.  The  covci-gla— »•-  were  dried,  stained, 
and  examined  microscopically.     Those  made  with  material  from  the 

following  cattle  were  found  to  contain  bacteria  identical  in  appear- 
ance with  tubercle  bacilli:  Nos.  l.  84,  L18,  825,  878,  -'.71.  and   I7<;. 


INOCULATION    TESTS    WITH    GUINEA    PIGS.  9 

The  number  of  bacilli  per  cover-glass  varied  with  different  cattle, 
and  on  different  days  with  the  same  animal,  from  0  to  25,  and  were 
usually  a  little  more  numerous  in  the  rectal  scrapings  than  in  the 
feces.  -  In  some  cover-glasses  made  with  shreds  of  mucus  picked  from 
the  feces  the  bacilli  were  much  more  numerous  and  in  some  instances 
innumerable. 

Cover-glass  preparations  similarly  made  with  feces  and  rectal 
scrapings  from  nontuberculous  cattle  were  found  to  be  free  from  any- 
thing resembling  tubercle  bacilli. 

With  a  simple  microscopic  examination  it  is  difficult  to  distinguish 
between  tubercle  bacilli  and  some  harmless  micro-organisms  known 
as  acid-fast  bacteria.  At  first  it  was  believed  that  the  bacilli  in  the 
preparations  belonged  in  whole  or  in  part  to  the  latter  group,  but 
this  view  was  not  tenable  after  it  was  discovered  that  similar  bacilli 
could  not  be  found  in  material  from  nontuberculous  cattle. 

INOCULATION    TESTS  WITH   GUINEA   PIGS. 

To  establish  absolutely  that  the  bacilli  were  virulent  tubercle  germs, 
a  series  of  inoculation  tests  with  small  animals  was  undertaken. 

Two  lots  of  guinea  pigs  were  inoculated  from  each  of  the  following 
cattle:  Nos.  1,  84,  113,  325,  373,  374,  and  384,  one  lot  with  feces  and 
the  other  with  scrapings  from  the  rectal  mucosa.  Cattle  Nos.  329 
and  372  were  omitted  from  the  inoculation  experiments,  as  they  had 
given  negative  results  with  microscopic  examinations,  and  cow  No. 
476  was  received  too  late  to  be  included. 

The  guinea  pigs  were  inoculated  under  the  skin  on  the  inside  of 
the  right  thigh;  each  received  an  amount  of  material  equivalent  in 
weight  to  about  one-eighth  of  a  grain,  and  more  than  25  per  cent  of 
them  became  affected  with  septicemia  and  died  before  a  tuberculous 
affection  had  time  to  develop.  The  results  obtained  with  the  animals 
that  lived  long  enough  to  contract  tuberculosis  are  as  follows: 

Cow  No.  1.— Guinea  pigs  inoculated  April  28,  1906,  with  feces  did 
not  become  tuberculous;  those  inoculated  on  the  same  day  with  scrap- 
ings from  the  rectal  mucosa  were  found  on  post-mortem  examination 
to  be  affected  with  tuberculosis.  Guinea  pigs  inoculated  June  19, 
L906,  with  feces,  as  well  as  those  inoculated  with  scrapings  from  the 
rectal  mucosa,  were  found  on  post-mortem  examination  to  be  affected 
with  tuberculosis.  Guinea  pigs  inoculated  June  27,  1906,  with  feces, 
as  well  as  those  with  scrapings  from  the  rectal  mucosa,  remained  free 
from  tuberculosis. 

We  have  from  this  cow  one  positive  and  two  negative  results  with 

feces  and  two  positive  and  one  negative  with  scrapings  from  the 

rectal  mucosa.     It  should  be  borne  in  mind  that  the  subcutaneous 

inoculation  of  guinea  pigs  with  cattle  feces  can  not  be  regarded  as  a 

30311— No.  90— 07  m 2 


10  hWi.i  i:    i  ROM     i  i   Si  ft  i  i  ■""  I    OATH  I  - 

.Irli.Mi.  i.  i  for  the  prosoncs  of  tubercle  bacilli,  ami  this  u  to  nearly 

thfl  MM  extent  tiTlfl  of  material  xraped  fnun  the  rectal  mucosa,  w  hieh 

U   QOmpOflOd    largely  of   feet-.      Cattlt    fece-  air   a   complex    -ub-tan<e 

relatixe   to   the    number   and    <Ii ir»'i««nt    kinds   of   bacteria    OOPf incd. 

ii  inoeolttion  la  followed  by  a  lootl  inflammation  tod  suppuration. 

ami  hence  the  tubercle  bacilli  that  arc  present,  if  their  number  b 

few,  have  every  chance  to  Im>  overcome  by  moiv  rapidly  growing 
organisms.  The  pathological  condition-  produced  by  the  latter  ma\ 
in  theiDSarreB  be  sufficient  to  prevent  the  tubercle  bacilli  from  cstah 
lishing  them-clves.  That  the  acid-fast  l>actcria  observed  in  the 
feces  of  cow  No.  1  are  certainly  infection-  tubercle  bacilli  IS  demon- 
strated absolutely  by  the  occurrence  of  tuberculosis  among  the 
guines  pigs.  That  the  feces  and  the  Bcrapings  from  the  rectal 
mucosa  inoculated  into  guines  pigs  that  remained  free  from  tuber 
cnlosis  did  not  contain  infectious  tubercle  bacilli  can  not  U'  asserted 
positively.    It  is  quite  likely  that  the  bacilli  were  present  hut  did  not 

have  a  chance  to  gel  actually  into  the  ti— ue-.  and  this  view    i-  -up 

ported  by  the  fact  that  acid-fast  bacteris  were  shown  to  Ih>  present 
in  the  feces  of  the  cow  on  each  of  the  three  days  on  which  the  inocu- 
lations were  made. 

Cur  .Xi>.  84. — Guines  pigs  inoculated  May  *_\  L906,  with  feces  did 
not  become  tuberculous;    those  inoculated  with  Bcrapings  from  the 

rectal  mUOOSB  were  found  on  po-t -mortem  examination  to  be  affected 
with  tuberculosis.  Guines  pi«rs  inoculated  on  other  days  from  this 
COW   died   affected    with   septicemia   before  tuberculosis   had    time   to 

develop.  *<. 

Con-  \o.  II. i. — Guinea  pigs  inoculated  with  either  feces  or  scrap- 
ings from  the  rectal  mucosa  on  April  27,  1906;  June  19,  L906,  and 
June  27.    L906,   were  all   found   on   post-mortem   examination    to  be 

affected  with  tuberculosis. 
Cows  Xox.  .  574,  and  384* — Guinea  pigs  inoculated  with 

free-   and   scrapings    from   the   rectal   mUOOSS   either  died    from   sep 

ticemia  before  tuberculosis  had  time  to  develop  or  were  found  to  be 

free  from  lesions  of  tuberculosis  on  post-mortem  examination. 

It  WSJ  shown   in   another  experiment      that    the  acid-fa-t    bacteria 

microscopically  demonstrated  in  the  feces  of  cow-  No-.  .'.71  and  B84 
were  virulent  tubercle  bacilli.    The  feces  in  the  experiment  referred 

to  were  fed  to  four  bogs  with  the  result   that   three  of  them  U'came 

affected  with  tuberculosis. 
The  reasons  why  the  inoculation  of  guines  pip-  with  feces  is  not  s 

delicate  test   for  the  pre-elice  of  tubercle  bacilli  do  not  apply  when  the 

feces  are  swallowed.  There  i-  no  inflammation  or  suppuration  in  the 
intestine  caused  by  swallowing  large  numbers  of  bacteria  of  the  kind 

«s<v  Bulletin  88,  Banra  «>r  Animal  Indostrr. 


SUMMARY    OF    EXAMINATIONS.  11 

ordinarily  contained  in  the  feces  of  cattle.  Bacteria,  excepting  those 
that  are  causative  agents  of  specific  diseases,  if  they  pass  through  the 
uninjured  wall  of  the  stomach  or  bowels,  are  rapidly  destroyed  and 
cause  no  marked  objectionable  condition  and  no  determinable  patho- 
logical lesions.  That  tubercle  bacilli,  on  the  other  hand,  may  pass 
through  the  uninjured  wall  of  the  intestine,  without  causing  local 
lesions,  is  claimed  on  the  basis  of  experimental  evidence. 

SUMMARY  OF   FECES   EXAMINATIONS. 

To  sum  up  the  results  as  far  as  we  have  gone,  among  seven  natural 
cases  of  tuberculosis,  we  have  five,  or  71.43  per  cent,  that  were  found 
on  microscopic  examination  to  be  passing  tubercle  bacilli  in  their 
feces,  and  the  two  cattle  that  failed  to  show  bacilli  were  a  cow  with 
an  affection,  strictly  "  closed,"  limited  to  one  post-pharyngeal  gland, 
and  a  young  steer  in  which  the  presence  of  tuberculosis  would  not 
have  been  suspected  without  a  tuberculin  test. 

The  feces  of  four  of  the  five  cattle  were  used  in  inoculation  tests 
and  were  found  to  be  infectious  in  two  cases.  To  these  a  third  must 
be  added,  as  subsequent  inoculation  tests  hereinafter  described  will 
show. 

Three  cows  that  were  fed  culture  of  tubercle  bacilli  showed  the 
presence  of  the  bacilli  in  their  feces  on  microscopic  examination,  and 
that  the  feces  were  infectious  is  shown  for  one  cow  by  guinea  pig 
inoculations  and  for  the  other  two  by  the  hogs  that  were  fed  with 
their  feces  in  an  earlier  experiment.  With  this  evidence  we  can  not 
doubt  that  the  tubercle  bacilli  that  are  swallowed  by  cattle  pass  in 
part  through  the  entire  length  of  the  digestive  tract  and  out  through 
the  rectum  without  losing  their  infectiousness. 

Animals  do  not  expectorate.  The  infectious  material  that  is  ex- 
pectorated by  tuberculous  persons  has  its  counterpart  in  tuberculous 
animals,  but  it  is  swallowed  and  not  thrown  out  as  sputum.  The 
absence  of  real  cavity  formation  in  the  lungs  of  cattle,  such  as  occurs 
in  tuberculous  human  lungs,  does  not  seem  to  militate  against  the 
number  of  bacilli  that  may  pass  into  the  environment  of  tuberculous 
cattle.  It  must  not  be  supposed  that  the  occurrence  of  the  bacilli  in 
the  feces  of  the  cattle  affected  with  naturally  acquired  tuberculosis 
was  due  to  intestinal  disease,  as  tuberculosis  of  the  intestinal  mucosa 
of  cattle  is  an  extremely  rare  affection. 

TESTS   OF   SALIVA,    NASAL   DISCHARGE,    URINE,    AND   MILK. 

The  saliva,  nasal  discharge,  and  urine  of  two  cows — Nos.  1  and 
113 — and  the  milk  of  three  cows — Nos.  84,  372,  and  373 — were  tested 
for  tubercle  bacilli  by  microscopic  examination  and  guinea-pig  inocu- 
lation, and  the  milk  further  by  ingestion  experiments. 


12  i>\n..i  i:  i  ton   i  urn  m  i  lous  oati  h.. 

The  mierowopie  examination-  were  all   i  ■  and  the  inoeula- 

lions    were    likewise    negative,    with    I  In-   exception   of   1 1 1»-   saliva    « » f 

S'o.   l  i:i,  which  invariably  produced  tuberculosis,    Tin  milk 
was  fed  to  a  large  number  of  guinea  pigs  for  long  periods  <»f  time, 

ami  other  guinea  |>ij-r-  «nv  Injected  with  it.  intra-abdominally.  from 
t  i  in**  to  time,  without  causing  disease  of  any  kino!. 

The  Dline  of  the  rows  was  drawn   from  their  Madden  through  a 

catheter  with  antiseptie  precautions  and  placed  for  thirty  minutes 
in  the  tubes  ol  I  small  electrical  centrifugal  machine  that  made 
2,000  revolutions  per  minute.  As  the  specific  gravity  of  tubercle 
bacilli  is  comparatively  high,  had  any  been  present  in  the  urine  this 
treatment  would  have  thrown  them  to  the  bottom  of  the  tubes. 
Only  the  lower  third  of  the  urine  in  each  tube  was  used  for  i  taking 
intra-abdominal  injections,  and  cadi  guinea  pig  injected  receivod  ■ 
dose  of  .">  cubic  cent  imeta 

The  microscopic  and  inoculation  tests  with  -aliva.  nasal  discharge, 
and  urine  from  cow-  No-.  1  and  118  wire  twice  repeated,  giving 
three  tests  of  each  kind  of  material,  each  test  on  a  different  day. 
The  milk  from  cow-  Nos.  84,  372,  and  373  was  removed  from  their 
udders  with  proper  care  to  prevent  its  contamination  with  feces. 

The  absence  of  tubercle  bacilli  from  the  urine  of  cow-  No-.  1  and 
113,  especially  from  that  of  the  latter,  indicates  that  they  are  rarely 
or  never  passed  in  the  urine  unless  the  genito-Ulinary  organs  are 
affected.  The  condition  of  the  two  cow-  relative  to  that  of  the  other 
cattle  strengthens  this  inference,  as  a  larger  number  of  positive  re 
stilts  wen'  obtained  with  the  inoculation  of  their  feces  ami  scrapings 
from  their  rectal  mucosa  than  with  similar  material  from  other 
cattle;  and,  further,  the  saliva  of  one  of  them  (No.  118)  infected 
every  guinea  pip  inoculated  with  it.  Hut  neither  the  urine  tests  nor 
the  cattle  were  sufficient  in  number  for  fully  reliable  negative  con- 
clusions, and  this  subject  will  receive  further  attention  in  the  future 
if  material  for  additional  investigations  can  Ik-  obtained. 

•  It  was  a  source  of  surprise  that  no  positive  results  followed  the 
inoculations  with  nasal  discharge,  because  the  location  of  the  nasal 
chamlwr-  -eem-  well  adapted  for  their  frequent  infection  with  ma- 
terial expelled  from  the  lung.  Cow  No.  119  suffers  with  frequent 
severe  paroxysms  of  coughing,  during  which  her  mouth  is  open  and 
the  air  is  largely,  if  not  wholly,  impelled  through  it.  This  ma\ 
count  for  the  presence  of  tubercle  bacilli  in  her  saliva  and  their 
absence  from  her  nasal  discharge. 

•  Subsequent  llCTMCOPk  examinations  of  the  saliva  of  emv  No.  11."..  In 
cover-RlasaeH  made  from  the  sediment  in  tulns  in  whi.h  it  was  mixed  with 
normal  unit  solution  ud  then  (vntrifim.ilized.  showed  1 1  ■•  -  nresenet  of  tubercle 
bacilli. 


THE    REAL   DANGER   FROM    TUBERCULOUS   CATTLE.  13 

Cow  No.  1  is  much  less  severely  affected  than  No.  113,  and  the  ab- 
sence of  positive  results  from  inoculations  with  her  saliva  and  nasal 
discharge  is  attributed  to  the  infrequency  and  mildness  with  which 
she  coughs.  Her  cough  is  rarely  more  than  a  gentle  effort  to  clear 
her  throat,  and  any  substance  expelled  from  her  lung  would  barely 
pass  her  fauces  and  would  be  swallowed  without  reaching  the  for- 
ward portions  of  her  mouth.  The  regurgitation  and  remastication 
of  food  that  is  practiced  naturally  by  ruminants  would  tend  to  clear 
her  throat  as  much  as  to  infect  it  with  swallowed  infectious  material. 
The  infectious  material  expelled  from  the  lung  and  swallowed  does 
not  necessarily  lodge  in  the  rumen,  from  which  regurgitation  takes 
place,  and  certainly  does  not  become  as  thoroughly  and  evenly  mixed 
with  the  contents  of  the  rumen  as  it  is  with  the  feces. 

The  absence  of  positive  results  from  the  inoculations  and  feeding 
tests  with  milk  is  in  perfect  harmony  with  the  writers'  past  experi- 
ences with  milk  from  tuberculous  cows  with  healthy  udders  when  the 
milking  is  done  with  proper  care  against  the  introduction  of  infec- 
tious material  that  is  not  associated  with  the  interior  of  the  udder 
or  the  milk-secreting  structures.  The  danger  that  milk  may  become 
infected  from  the  environment  of  tuberculous  cows  is  so  great  that 
we  are  justified  in  asserting  that  the  few  positive  results  we  have 
had  during  many  years  with  intra-abdominal  injections  of  guinea 
pigs  with  milk  from  tuberculous  cows  with  unaffected  udders  were 
not  due  to  tubercle  bacilli  that  were  drawn  with  the  milk,  but  to 
tubercle  bacilli  that  dropped  into  it  or  into  the  milk  pail  from  the 
exterior  of  the  cow,  despite  all  precautions  to  the  contrary.  Since 
it  does  not  seem  reasonable  for  tubercle  bacilli  to  leave  the  body  with 
the  urine  unless  the  genito-urinary  apparatus  is  affected,  similarly 
it  does  not  seem  reasonable  for  them  to  pass  out  with  the  milk  through 
a  healthy  udder. 

FECES  IN  MILK  THE  REAL  DANGER  FROM  TUBERCULOUS  CATTLE. 

The  results  of  the  tests  point  to  the  conclusion  that  the  real  danger 
from  tuberculous  cattle  lies  in  the  manner  in  which  tubercle  bacilli 
are  disseminated  with  their  feces. 

The  average  number  of  acid-fast  bacilli  found  in  the  feces  of 
tuberculous  cattle — leaving  the  greater  number  in  the  rectal  scrap- 
ings and  selected  shreds  of  mucus  out  of  consideration — is  6  per 
cover-glass.  That  these  bacteria  are  tubercle  bacilli  has  been  suffi- 
ciently demonstrated  by  the  positive  results  obtained  with  the  inocu- 
lation tests  and  by  their  absence  from  the  cover-glasses  prepared 
with  the  feces  of  nontuberculous  cattle.  Now,  let  us  calculate  what 
this  signifies  as  to  the  amount  of  infection  that  may  be  scattered  by 
a  single  tuberculous  cow  in  one  day. 


II  DANOKK    FltoM     II    |:|  i:<  TI.i  >l'S    CATT1.K. 

The  cover-glasses  were  carefully  weighed  on  a  delicate  balance 
before  and  after  spreading  n  layer  of  feces  on  them.  The  amount 
of  moist  feces  per  oover-glast  irai  (bund  t<»  have  ■  maximum  weight 

of  one-thirtieth  of  n  grain;  it   was  usually  less,  and   frequently  not 

inoic  than  one  half  ai  much.    When  one  of  the  prepared  cover 

«rln--*-  i-  examined  with  the  microsco|)e  the  fir-t  condition  noticed  if 
that  only  a  portion  of  it.  rarely  one  half,  is  sufficiently  transparent 
for  the  detection  of  tubercle  bacilli.      It  is  reasonahle  to  assume  that 

the  thicker,  opaque  portions  of  the  film  of  feces  ere  heavier  and  con- 
tain i  larger  number  of  bacilli  than  the  lighter,  transparent  portione; 
hence,  the  tubercle  bacilli  that  come  into  view  after  prolonged  learoh 

are    le-s   than    half    the    number   actually    present.     To   one    who    H 

familiar  with  microscopic  work  it  would  not  appear  anreaaonable  if 
we  made  the  flat  assertion  that  it  is  impossible  to  find  more  than  10 
per  cent  of  the  tubercle  germs  that  arc  present  in  cover-glassee  of  the 

kind    we   made    for   our   examinations.     Hut    it    is   not    Decesatrjf    to 
present   the  fact   in  this  extreme.     If  we  take  only  the  actual  av. f 
age  number  of  tubercle  bacilli  seen,  and  the  maximum  weight  of 

feces  per  cover-glass,  we  have  ,;  bacilli  in  one-thirtieth  of  a  grain  of 
feces,  and  \\ c  can  not  avoid  feeling  amazed  at  the  amount  of  infec- 
tion which  this  represent-  as  leaving  the  body  of  a  tuberculous  cow 
daily. 

A  cow  of  average  size  panoni  about  80  pounds  of  moist  feces  each 
day.  and  if  the  whole  of  this  mass  could  U-  spread  on  cover-glassos 
similar  to  our  preparation,  it  would  be  sufficient  to  make  6,300,000 
preparations,  which  would  contain  37,800,000  microscopically  de- 
monstrable tubercle  bacilli. 

It  is  a  significant  fact  that  our  microscopic  examinations  indicate 
that  the  bacilli  in  the.  feces,  excepting  those  in  the  shred-  and  masses 
<»f  mucus  that  do  not  enter  into  the  present   calculation,  are  evenly 

distributed,  bo  that  we  do  not  have  some  portions  of  the  feces  that  are 

very  infectious  and  other-  that  are  innocuous.  Practically  it  is  all 
infectious,  and  every  part  of  it  is  dangerous,  and  the  mucus  shreds 
alone  show  extreme  infectiousness.  The  even  distribution  of  the 
bacilli  likewise  indicates  that  they  entered  the  inte-tine  at  the  upper 
end  of  the  digestive  tract,  as  a  considerable  amount  of  churning. 
such  as  the  food  receives  in  the  stomach  and  intestines,  is  required  to 

effect  this  distribution. 

Tuberculous  persons  from  whom  tubercle  bacilli  are  being  dssawav 
inated  can  in-  taught  to  use  various  precautions  that  will  reduce  to  a 

minimum  the  danger  to  health  in  their  environment.  Sputa  can  be 
expectorated    into    receptacles   containing    germicidal    fluids,   and    a 

cloth  can  Ih>  held  before  the  mouth  <luring  paroxy-m-  of  coughing 
and  at  once  treated  so  a-  to  destroy  the  infection-  material  that    i- 


HOW    MTLK    IS   INFECTED    WITH    TUBERCLE    BACILLI.  15 

impelled  against  or  into  it.  Such  persons  can  have  individual  sleep-  • 
ing  apartments,  and  they  should  be  prevented  from  coming  into  con- 
tact with  articles  of  diet  that  are  used  by  healthy  persons.  Their 
own  individual  generosity,  when  they  are  informed  of  their  condi- 
tion and  its  danger  to  health,  will  with  rare  exceptions  induce  them  to 
take  many  precautions  for  the  safety  of  their  families  and  associates. 
Healthy  persons,  when  they  are  informed  of  the  danger  involved  in 
close  contact  with  those  affected  with  tuberculosis,  and  know  that  a 
chronic  cough  must  be  regarded  as  a  very  suspicious  circumstance, 
can  do  much  for  their  own  protection  by  avoiding  association  on 
terms  of  close  intimacy  with  persons  who  are  actually  or  probably 
tuberculous. 

With  cattle  we  have  a  different  state  of  affairs.  Effective  germi- 
cidal substances  are  too  expensive  and  their  proper  application  to 
large  masses  of  feces  daily  is  too  difficult  and  troublesome  for  prac- 
tical purposes.  Feces  are  dropped  everywhere  in  the  environment 
of  cattle — in  stables,  fields,  and  barnyards,  and  on  roadways.  They 
are  splashed  on  the  bodies  of  cattle,  and  frequently  cattle  lie  down 
and  get  their  bodies  coated  with  them,  and  this  is  especially  true  of 
the  parts  of  the  body  close  to  the  udder.  Feces  are  thrown  against 
partitions  of  stalls  and  walls  of  stables  and  are  promiscuously  switched 
about  by  the  soiled  tails  of  animals,  and  no  precaution  or  measure  of 
cleanliness  can  entirely  prevent  them  from  getting  into  the  milk  pail 
occasionally  and  on  the  hands  and  clothing  of  the  stable  attendants 
and  milkers  frequently.  We  have  seen  large  quantities  of  milk 
strained  in  many  dairies,  but  have  not  found  the  dairy  in  which  the 
milk  was  removed  from  the  cows  with  a  degree  of  cleanliness  so  per- 
fect that  the  cloth  or  screen  through  which  it  was  strained  did  not 
show  the  presence  of  some  cattle  hairs  and  fragments  of  a  substance 
suspiciously  like  feces.  In  some  dairies  the  quantity  of  feces  that 
enters  the  milk  pail,  both  fresh  and  dry,  to  judge  from  that  which 
collects  in  the  strainer  through  which  it  is  poured,  is  comparatively 
large.  The  precautionary  measures  that  can  be  used  by  the  dairy- 
man are  limited  by  the  price  of  milk.  He  can  not  afford  to  use  meas- 
ures the  cost  of  which  is  so  great  that  their  application  would  convert 
his  business  into  a  philanthropic  enterprise. 

Regarding  the  dairy  industry,  we  know  the  two  following  impor- 
tant facts:  (1)  That  the  commonest  disease  with  which  cows  are 
affected  is  tuberculosis,  and  (2)  that  milk  in  some  form  reaches  prac- 
tically all  persons.  The  person  who  does  not  use  milk,  cream,  butter. 
or  cheese  is  a  rare  exception  to  a  general  rule,  and  the  family  that 
uses  no  fresh  dairy  product  can  hardly  be  said  to  exist. 

When  we  know  how  completely  cattle  feces  may  be  charged  with 
tubercle  bacilli   and   how  easily   milk  may   be  infected   from  this 


l*'i  l>\N(il-.u    nOM     i  i  i-i  i:<  (7LOU8   <   \i  im. 

soimv,  and  contemplate  \\w^  fact,  keeping  in  mind  tin*  wide  distribu- 

t  ion  that  dairy  product-  have,  and  add  to  OUT  knowledge  BODfl  of  the 

results  recently  obtained  and  published  by  competent  mvestigetora, 
are  must  conclude  that  the  eradication  of  tuberooloaif  among  cattle 

can  not  In-  tOO  vigorously  urged  Of  pursued. 

Our  own  inveetigationi  have  shown  thai  pulmonary  tuberculosis  n 
the  moat  common  form  of  the  diasaae  in  animals,  irrespective  ol  the 
point  at  which  the  tuberculous  infection  enten  the  body,  and  that 
tubercle  bacilli  may  pan  through  the  intestinal  wall  and  reach  the 
lung  without  causing  risible  disease  of  the  intestinal  mucosa. 

Nicholas  and   Dcscosand   IJavenel   proved  by   feeding  healthy  dogB 

on  tuberculous  fluids  and  examining  the  chyle  in  the  thoracic  duct  i 

few  hours  later  that  tubercle  bacilli  may  readily  pass  through  the 
intestinal  wall  and   infect  the  animal  without  causing  lesions  in  the 

Intestines. 

Per  the  benefit  of  readers  who  are  not  informed  on  the  subject  «>f 
anatomy  it  may  Im>  well  to  say  that  the  thoracic  duct  i^  the  common 

trunk  <>f  all  the  lymphatic  reesels  that  drain  the  abdominal  cavity 

and  the  organs  contained  in  it.  and  an  additional  large  portion  of  the 
body,  and  that  it  discharges  its  contents  into  the  anterior  vena  cava. 
one  of  the  large  veins  in  which  the  blood  is  returned  to  the  heart. 
The  material  discharged  by  the  dud  into  the  vein  is  carried  with  the 
blood  directly  to  the  heart  and  pumped  by  the  heart  to  the  lung, 
where  it  i>  filtered  through  1 1  »**  exceedingly  line  capillary  network 

in  which  the  blood  is  arterialized.  It  can  readily  be  seen  that  tubercle 
bacilli  that  have  passed  through  the  intestinal  wall  and  through  the 
lymphatics  into  the  thoracic  duct  have  a  clear  way  to  reach  and  infect 
the  lung. 

Vallc'e  calls  attention  to  the  fact  that  the  lung  i>  the  favorable  loca- 
tion of  the  tubercle  bacillus  in  all  species  of  animals,  and  In-  made 
experiments  that  indicate  that  infection  through  the  digestive  tract 
constitutes  a  mode  of  inoculation  which  is  extremely  favorable  t<> 
the  production  of  pulmonary  tuberculosis.  He  concludes  that  inges- 
tion is  the  quickest  and  most  certain  method  for  the  tul>erculari/ation 
of  the  lymph  glands  associated  with  the  lung,  and  that  the  tubercle 
bacillus  may  paas  through  the  intestinal  wall  without  producing  ap- 
preciable lesions  in  the  mucous  membrane  of  the  intestine  or  in  the 
mesenteric  lymph  glands 

Bchloasman  and  St.  Kngle  found  that  tubercle  bacilli  introduced 

into  the  stomachs  of  guinea  pigs  by  means  of  a  laparotomy  could  !*• 
found  in  the  lungs  in  a   few  hour-.     Calmette  produced  pulmonary 

tuberculosis  <»f  a  goat  by  introducing  suspensions  <»f  tubercle  bacilli 

into  it>  rumen.     Cadeac  enoorts  after  careful   investigation  that   the 


TUBERCULOSIS    CONTRACTED    CHIEFLY   BY   INGESTION.'  17 

widely  accepted  hypothesis  of  the  transmission  of  tuberculosis  by 
inhalation  of  dust  from  dried  sputa  has  not  been  proven;  and  he 
showed  that  sputum  dries  slowly,  is  difficult  to  pulverize,  and  rapidly 
loses  its  infectious  character. 

PERSONS    PROBABLY    CONTRACT    TUBERCULOSIS    CHIEFLY    BY    INOKSTIOX. 

It  has  long  been  supposed  that  the  frequency  with  which  tubercu- 
losis occurs  among  persons  is  due  to  the  direct  infection  of  the  lung 
(probably  because  the  lung  is  most  frequently  affected)  with  sputum 
which  has  become  dried  and  pulverized  after  being  expectorated  by 
persons  affected  with  tuberculosis.  This  supposition  or  theory  is 
gradually  being  shown  to  be  erroneous,  (1)  because  sputum  does  not 
pulverize  easily  and  loses  its  infectious  character  in  a  short  time; 
(2)  because  the  greater  frequency  with  which  the  lung  is  affected  as 
compared  with  any  other  organ  of  the  body  is  accounted  for  in  a  way 
that  does  not  require  the  acceptance  of  the  theory  of  direct  infection 
from  the  air,  and  (3)  because  it  is  being  shown  by  a  number  of  in- 
vestigators that  tubercle  bacilli  may  pass  through  the  intestinal  wall 
without  injuring  it  and  thus  may  reach  the  lung,  and  that  the  inges- 
tion of  tubercle  bacilli  is  the  quickest  and  simplest  way  to  infect  the 
lung.  In  other  words,  the  inhalation  of  tubercle  bacilli  is  losing 
much  of  its  importance  in  the  minds  of  investigators,  and  the  swal- 
lowing of  tubercle  bacilli  is  gradually  supplanting  it  as  the  true  mode 
of  infection.  It  therefore  becomes  necessary  to  give  the  most  careful 
attention  to  the  sources  from  which  tubercle  bacilli  may  reach  our 
daily  food  and  drink. 

There  is  little  doubt  that  many  persons  become  affected  with  tuber- 
culosis by  breathing  tubercle  bacilli  in  an  infected  environment. 
Infectious  material  sprayed  from  the  mouths  of  tuberculous  persons 
lodges  in  the  upper  air  passages,  is  drawn  or  drops  into  the  mouth, 
and  is  swallowed  and  taken  up  by  the  intestines,  and  through  the 
lymph  channels  reaches  .the  lung.  Other  cases  result  from  tuber- 
culous persons  who  are  allowed  to  handle  and  prepare  food  and  to 
clean  and  care  for  kitchen  and  table  utensils. 

But  there  is  little  doubt  in  the  writers'  minds  that  tubercle  bacilli 
from  no  source  receive  a  wider  distribution  in  a  perfectly  fresh  state 
than  those  that  enter  the  milk  with  fragments  of  feces  from  tuber- 
culous cows.  As  we  have  already  pointed  out,  tuberculosis  is  the 
most  frequent  disease  with  which  dairj^  herds  are  affected,  and  milk 
has  an  enormously  wide  distribution.  It  is  taken  everywhere  on 
every  day  and  reaches  practically  every  person  on  every  day. 


18 


i>\\..i  i:    I'KuM     i  i  r.i  i:<  ri  m'H   .   \  i  1 1.1  . 


INKKCTlot   SNK.SS    .  >|      -.  .11  I  l>     Mil  K     SIIIIWN     l\\      IN...   I    I    v  I  |..\     i>|      ..(    I\l    \ 

nm, 

"  I "  1  *  •  — *  -  facts  make  it  desirable  to  know  something  definite  about  the 
Significance  of  1 1  »*-  frequently  unavoidable  introduction  of  free-  into 

milk,  ami  nm-  have  tried  t<>  gain  Light  <>n  the  subject  by  inoculating 
goinee  pigs  with  milk  into  which  small  fragments  of  feces  from 
tnbercnloofl  cows  were  placed  in  ■  manner  as  nearly  a«  |»<»  —  il»l«-  like 

that  which  OOCUn  IH  I  dairy  stable. 

Normal,  fresh  milk  from  healthy  cows  was  -oiled  with  mall  masses 

of  feces  from  cow-  NTos.  1.  M.  1  L8,  :{•_'."».  and  :'.7:'..     The  amount  intra 

dnced  into  each  Bample  «>f  milk  was  very  small,  about  as  mm  I 

would  enter  in   proportion  to  the  volume  of  milk   in  a  dairy  stable 

in  which  average  cleanliness  is  practiced.    Some  of  the  soiled  milk 
was   injected   without    further  treatment    and   some   was   -trained 
through  linen  doth  ami  then  injected.    The  injections  were  intra 
abdominal,  and  each  guinea  pig  received  i  doss  of  5  cubic  centi- 
meter-. 

To  make  sure  that  the  milk  DSed  in  \h\>  experiment  WSJ  free  from 
infectious  material  before  it   was  soiled  with  the  feces,  a  QUmber  of 

guinea  pigs  were  injected  with  it  from  time  to  time  in  its  pure  un- 

Boiled  state.  Such  guines  pigs  remained  well  until  they  were  killed, 
and  on  |>ost-mortetn  examination  were  found  to  be  free  from  lesions 
of  di-«-a-\ 

The  following  tables  give  the  results  obtained   with  the  injections 

of  -oiled  milk.  No  table  is  given  for  cow  No.  825,  as  no  tuberculosis 
was  caused  by  the  milk  soiled  with  her  feces.    In  all  other  respecta 

the  inoculations  were  identical  with  those  of  COW   No. 

Ittxultx  of   injrrtiii;/   i/uiioti    pdjtf    irilh    normal    milk    (from    htdlthu  rt>\ca)    xoihil 
irilh  frees  from  run     \<>.    I    i  I itheiriiloiis  i . 

MILK  not  STic.\l\i:i». 


if.'in~    Hut.- of  Injer- 
X  ti""- 


tune  19,1906 

■  1.. 

Ti.10    'to 

7611     do 


•  I.  ulh    > 


Id-mark*. 


July  24,  i9«»>  TubereokMtoof  liv<r.  »|.i«-«-t>.  sad  aMomtaa]  lymph  iriamK 

No  l«-sii -n-  of  illAoaw*. 

do TulxrruloMx  of  mi  Motoric  Klamlv 

TaberOOloriSOf  liTOr,  ipleco,  iiii'l  Hlwlominal  lymi.h  Klandn. 


mi 


MII.K   STRAINED  Tllltoroil  CLOTH 


June  19,1906    July  21.1906 

■  t.. 
l.i...-  A,  1906 
lui  ■ 


Qonenltotd  tabaroalaofc 
Do 

IH.-.I.  nff.it.il  will.  |Mrit..iiitl-. 

I-. 


•Except    where   1 1»«-   wnnl   "died"   I*   MOd    In    tin-   n-marka.    the  guinea   pljpi  remained 
allre  until  they  VON  klllr<l  for  port  ■Oft—  examination. 


RESULTS    OF    GUINEA-PIG    INOCULATIONS. 


19 


Results  of  injecting  guinea  pigs  with  normal  milk  (from  healthy  cows)  soiled 
with  feces  from  cow  No.  113  (tuberculous).11 

MILK  NOT  STBAINKIi 


No.  of 

guinea 

pig- 

Date  of  In- 
jection. 

Date  of 
death,  b 

Remarks. 

7503 
7504 

May  29,1906 
do 

July  23,1906 
do 

Generalized  tuberculosis. 
Tuberculosis  of  liver  and  spleen. 
Do. 

7505 

do 

do 

7506 

do 

do 

7507 

do 

do 

Tuberculosis  of  liver,  spleen,  and  abdominal  lymph  glands. 
Do. 

7508 

do 

do 

7573 
7574 

June    9,1906 
do 

do 

do 

Generalized  tuberculosis. 
Do. 

7575 

do 

do 

Do. 

7576 

do... 

do 

Do. 

7592 
7593 

June  18,1906 
do 

July  24,1906 
do 

Do. 

7594 

do 

do 

7595 

do 

do 

Tuberculosis  of  spleen. 

MILK   STRAINED  THROUGH  CLOTH. 


7596  June  18, 1906 

7597    do 

7696    do 

7599    do 


July  23,1906 

do 

do 

do 


Tuberculosis  of  liver  and  spleen. 
Generalized  tuberculosis. 

Tuberculosis  of  liver,  spleen,  and  abdominal  lymph  glands 
Do. 


"  In  connection  with  this  cow  it  should  he  observed  that  17  of  a  total  of  18  guinea 
pigs  inoculated  with  milk  that  was  soiled  with  her  feces  became  affected  with  tubercu- 
losis, and  that  the  amount  of  feces  added  to  the  milk  was  so  small  that  not  one  guinea 
pig  of  the  18  that  received  intraperitoneal  injections  became  affected  with  peritonitis. 

"Except  where  the  word  "died"  is  used  in  the  remarks,  the  guinea  pigs  remained 
alive  until  they  were  killed  for  post-mortem  examination. 

Results  of  injecting  guinea  pigs  with  normal  milk  (from  healthy  cotes)   so'tlcl 
with  feces  from  cow  No.  84  (tuberculous). 

MILK  NOT  STRAINED. 


No.  of 

guinea 

Pig- 

Date  of  injec- 
tion. 

Date  of 
death  .a 

Remarks. 

7638 
7639 
7640 
7641 
7642 

June  21,1906 

do 

do 

do 

do 

July  25,1906 
July     5,1906 
July  25,1906 
J  une  26, 1906 
July  25,1906 

Tuberculosis  of  lung,  liver,  and  spleen. 
Died,  affected  with  peritonitis. 
Tuberculosis  of  liver  and  spleen. 
Died,  affected  with  peritonitis. 
Tuberculosis  of  liver  and  spleen. 

MILK   STRAINED  THROUGH   CLOTH. 


7643 
7644 
7645 
7646 
7647 
7673 
7674 
7675 
7676 
7677 
7678 


June  21,1906 

do 

do 

do 

do 

June  22,1906 

do 

do 

do 

...  .do 

do 


Julv  25,1906 
June  22, 1906 

...   .do 

do 

do 

July   24,1906 

do 

do 

...  .do 

do   

do 


Tuberculosis  ol  liver  and  spleen. 
Died,  affected  with  peritonitis. 

Do. 

Do. 

Do. 
No  lesions  ol  disease. 

Do. 

Do. 

Do. 

Do 

Do. 


"  Except  where  the  word  "  died  "  is  used  in  the  remarks,  the  guinea  pigs  remained  alive 
until  they  were  killed  for  post-mortem  examination. 


•J  It 


|.\M  M      I  I    III   Kl    II 


ttrmilt*  of   iii  m  rtiiui  »/«»'""    /"'"*    "  HI'    normal   mill,    (from   lnnltliii  rotca)    soiled 

i  tuin  rxmUnu ), 


Mil.K   \i  1 1    s  i  i:  \i  m:ii 


N,, 

guinea 

pin 


.(  lii- 
nmi. 


l>nlr..fi|o»tll.«t 


Kciiinrk*. 


MSB 

Ti.Ji. 

ran 

T.M'.t 

7.V*) 
7V,I 

rat 

TOM 


.li  i  !>•'  JO, 1906 

Jane   7, 1900 


July  24.1906 
do 

.1.. 

JUM  "V.  1906 
June  10,1906 
July   -23,1900 


Ion*  <>f  dimaae. 
Do 

I).. 
I»... 
in.. i.  affected  wild  |..rit.mltl«. 

Generalised  tuiMTruioai*. 

Do. 

Do. 


• 

MILK  BTRA1NBD  THBOTJGU  CLOTS. 

MO 
7«M 
MB 
M0J 

JflJM  20.1900 

....do 

do 

July  24,1906 
do 

No  leakm  ..f  -iiM-me. 
Do 
Do 
Do. 

•Bscevt    wIhtc   Hi.-   wi.nl   Hdled"   la  uaed   In   the   r«Miiark«.    the  miliu-n    plan]    raoaajlMd 

nllv»>  until   tlii-y   WW*  klll*-<l  for  pi.st  inortPin  <>xamlnntlon. 

A-  lli«'  t;il)lcs  dlOW,  both  t In*  strained  and  Unstrained  milk  -oiled 
with  free-  from  COWS  No-.  1.  B4,  and  11:5.  and  the  mist  rained  milk 
Boiled  with  fiii--  from  cow  No.  :i7:'>.  were  infections  for  guinea  i>ij-r-- 
Add  to  this  cow  No.  825  with  negative  results,  and  we  have  one  cow 

that  wa-  fed  tnl>erele  bacilli  in  her  drinking  water  and  four  affected 

with  naturally  acquired  tuberculosis.    The  former  and  three  of  the 

latter  were  passing  tubercle  bacilli  in  their  fece-  in  sufficient  num- 
bers and  of  sufficient  virulence  to  make  the  infection  of  milk  exposed 
in  their  environment  easily  possible.  No  better  evidence  can  In-  pre- 
sented to  support  the  conclusion  that  the  presence  of  a  single  tuber- 
culous COW  in  a  dairy  -table,  even  if  her  milk  is  not  used,  should  not 
be  tolerated.  She  i-  a  direct  danger  to  the  healthy  cattle  that  .ire 
exposed  to  her.  and  may  Ih>  responsible  for  the  introduction  of  inf.. 
tious  material  into  their  milk,  and  thus  make  it  dangerous  for  u-e 
by  persons  or  animal-. 
It  must  not  l>e  supposed  that  the  cow-  assd  in  these  beats  wan 

old.  invalid  animal-.  BO  badly  effected  with  tuberculosis  that  no  run- 
-cientious  dairyman  would  retain  them  in  his  herd.  With  the  single 
exception  <>f  cow  No.  118,  their  condition,  a-  far  a-  could  U-  deter- 
mined by  a  -imple.  unaided,  physical  examinat ion.  \v:i-  batter  than 
that  of  the  majority  of  dairy  cow-  in  actual  u-e.  They  looked  better 
nourished,  and  their  hair  was  -moot her.  j_do— ier,  and  cleaner.  The 
slight,  infrequent  cough  with  which  they  were  affected  would  not 
have  attracted  the  attention  of  the  casual  observer,  and  might  have 
been  honestly  attributed  by  most  dairymen  to  dust  in  the  air  of  the 


FEEDING   AND    INOCULATION    TESTS.  21 

stable.  These  cows  illustrate  anew  the  fact  that  the  danger  from 
tuberculosis  does  not  rest  on  an  intensely  infectious  character  of  the 
disease,  but  on  its  insidiousness  and  concealed  and  secret  nature, 
which  enables  it  to  come  and  develop  and  spread  infection  without 
warning.  Strictly  speaking,  the  best  as  well  as  the  worst  cow  in 
appearance  relative  to  health  must  be  suspected  until  she  has  been 
proven  sound  by  a  tuberculin  test. 

ADDITIONAL   FEEDING  AND   INOCULATION   TESTS. 

Two  additional  tests  were  made  for  the  presence  of  tubercle  bacilli 
in  the  environment  of  tuberculous  cattle.  (1)  The  mixed  feces  of 
cows  Nos.  1  and  113  were  fed,  together  with  cornmeal  and  bran,  to 
four  healthy  hogs,  and  (2)  earth  from  the  outside  of  the  stable  in 
which  the  tuberculous  cattle  were  housed,  near  the  door  through 
which  the  manure  was  removed,  was  microscopically  examined  and 
used  for  guinea-pig  inoculations. 

Before  the  feeding  experiments  began  the  hogs  used  in  them  were 
tested  with  tuberculin  without  showing  a  reaction,  and  hence  must 
be  regarded  as  originally  free  from  tuberculosis.  The  feeding  was 
continued  about  six  weeks,  and  shortly  after  it  was  stopped  the  hogs 
were  again  tested  with  tuberculin.  With  the  second  tuberculin  test 
all  four  gave  the  reaction  indicative  of  the  presence  of  tuberculosis. 
When  the  hogs  were  killed  and  examined  post-mortem  it  was  found 
that  one  was  affected  with  tuberculosis  of  the  lung  and  liver  and  the 
submaxillary,  prescapular,  and  mesenteric  lymph  glands,  and  the 
other  three  with  tuberculosis  of  the  submaxillary  lymph  glands. 
The  submaxillary  glands,  not  alone  from  the  results  obtained  with 
this  experiment,  but  also  from  other  observations  on  a  larger  number 
of  animals,  must  be  regarded  as  the  first  structures  in  the  bodies  of 
hogs  to  become  affected  when  they  contract  tuberculosis  through  the 
ingestion  of  infectious  material. 

The  fact  that  the  four  hogs  contracted  tuberculosis  shows  that  the 
feces  contained  active,  virulent  tubercle  bacilli,  and  likewise,  as  was 
pointed  out  in  a  former  publication,"  that  much  of  the  tuberculosis 
that  occurs  among  hogs  may  be  due  to  a  method  of  feeding  exten- 
sively practiced  in  the  West — turning  hogs  behind  cattle — when  in- 
sufficient care  is  taken  against  the  presence  of  tuberculosis  among  the 
cattle.  Hogs  that  are  exposed  to  cattle  feces  or  have  access  to  manure 
heaps  from  stables  in  which  cattle  are  kept  may  at  any  time  become 
tuberculous  if  the  cattle  are  affected.  This  practice  and  the  feeding 
of  skim  milk,  especially  when  tubercle  bacilli  have  been  concentrated 
in  it  by  the  separation  of  the  cream  from  the  milk  with  a  centrifugal 

o  Bulletin  88,  Bureau  of  Animal  Industry. 


M  h\N«.li:    PROM     I  I'Bl  R("l  \  i  i  ll  . 

machine,  arc  probably  the  most  f rtM|ii«-iil  OBUaCB  of  fetlberOOlOBU  ISDJOlIg 
IftOgB.     Thai    tuU'iele  bacilli   may   Im-  dropped,  ipkfflhfld,  sprayed,  or 

switched  into  milk  when  it  it  ftMaintrd  from  tuberculous  cows  or  baa 
Ihhmi  ox|n>s(mI  to  the  environment  of  tuberculous  oettlo  has  already 
been  pointed  out,  but  cm  not  be  too  often  repented* 

The  microscopic  examination  of  the  earth  from  the  OQteide  of  the 

stable  in  which  the  tul>erculous  cattle  used  in  these  experiments  were 

kept  ic\calc.|  the  preeence  of  nnmeroni  acid-fast  bacilli,  licet  <»f 
the  guinea  pig-  inoculated  with  spechnena  of  this  earth  died  from 

septicemia,   and    those    that    lived    until    they    were    killed    for    |><.-t 

mortem  examination  showed  either  no  lesions  of  dieenee  (in  ■  few 
instances)  or  very  extensive  lesions  that  could  easily  be  mistaken 

Cor  tuherculosis.  hut    were  shown  by   microscopic  examination   to  be 

nontnbercnlons  and  due  to  the  action  of  other  bacteria  than  tubercle 

bacilli.  Hence  we  can  not  assert  definitely  that  the  acid-fa-t  bac- 
teria found  in  the  samples  of  earth  on  microscopic  examination  were 
tubercle  bacilli,  as  acid-fast  bacteria  are  very  common  in  the  soil  in 
and  around  stables  and  barns. 

CONCLUSIONS. 

1.  Tubercle  bacilli  are  disseminated  with  the  feces  of  tul>erculous 
cattle.     This   is  shown   to  l>e   the  case   by   microscopic  examination. 

by  inoculation  tests  with  guinea  pigs,  and  hy  ingestion  experiments 
with  hogs. 

2.  Feces  are  the  most  dangerous  factor  in  the  dissemination  of 

tubercle  bacilli   by  cattle  affected   with   tuherculosis.      In  this  res|>ect 

feces  must  be  regarded  as  having  a  place  with  cattle  similar  to  that 
commonly  accorded  to  >puta  with  tuberculous  personal 

3.  It  is  not  alone  the  feces  of  visibly  affected  cattle  which  dissemi- 
nate tuberek  bacilli  in  a  way  that  i-  dangerous  to  man  and  animal-, 
hut  also  the  feces  of  cattle  BO  slightly  affected  that  the  diagnosis  of 
tuberculosis   with   them   depends  entirely   on   the   application   of  the 

tuberculin  teat 

4.  Tubercle  bacilli  that  are  -wallowed  by  cattle  are  to  a  great 
extent  passed  entirely  through  the  digestive  tract  and  out  with  the 
feces  without  loss  of  infect  iouslie— .  A-  cattle  do  not  expectorate. 
the  infection-  matter  that  i-  COUghcd  up  from  their  lungs  i-  swal- 
lowed, passed  through  their  bodice,  and  scattered  with  their  feces. 

.">.    Bacilli   may  reach  the  environment   of  tuberculous  cattle   from 

their  mouths,  hut  this  is  evidently  of  rare  occurrence  compared  with 

the  di-scinination  through   fooCB,  especially  when  the  cattle  are  not 

visibly  tuberculous. 

6.  The  nasal  discharge  of  tuU'rculotis  cattle  wa-  found  to  be  five 
from  infectious  material.     Cow    No.   11.',  i-  so  severely  affected  with 


conclusions.  •    23 

tuberculosis  that  this  freedom  in  her  case  seems  to  indicate  that  nasal 
discharge  rarely  contains  tubercle  bacilli.  It  is  possible  that  a  larger 
number  of  tests  may  modify  this  conclusion. 

7.  Urine  is  probably  free  from  tubercle  bacilli  when  the  genito- 
urinary organs  are  riot  affected  and  no  infectious  material  has  been 
introduced  into  it  after  it  has  been  passed.  The  practical  signifi- 
cance of  this  conclusion  lies  in  its  bearing  on  the  question  whether 
tubercle  bacilli  are  ever  thrown  out  by  tuberculous  subjects  through 
unaffected  secretory  organs  with  otherwise  normal  secretions. 

8.  Milk  from  tuberculous  cows  with  unaffected  udders  we  believe 
to  be  free  from  infection  until  it  has  become  contaminated  with  feces 
or  some  other  material  that  contains  tubercle  bacilli  from  the  outside 
of  the  cows  or  from  their  environment;  that  is  to  say,  it  is  not  be- 
lieved that  tubercle  bacilli  are  eliminated  with  the  milk  from  tuber- 
culous cows  unless  disease  of  the  udder  or  structures  connected  with 
it  is  present.  This  conclusion  is  drawn  from  the  present  series  of 
investigations  and  is  supported  by  our  earlier  work  relative  to  the 
milk  of  tuberculous  cowts.  The  present  investigations  include  only 
a  few  cows  and  a  comparatively  small  number  of  guinea  pigs.  The 
earlier  investigations  extend  over  a  dozen  years,  during  which  milk 
from  scores  of  tuberculous  cows  was  injected  into  the  abdominal 
cavities  of  hundreds  of  guinea  pigs. 

When  milk  injections  into  guinea  pigs  are  made  by  pathologists 
or  bacteriologists  as  a  test  for  the  presence  of  infectious  material,  un- 
usual, though  not  always  sufficient,  precautions  are  taken  at  the  time 
of  milking  to  protect  the  milk  from  contamination  with  foreign 
matter  of  any  and  every  kind  that  may  reach  it  from  the  exterior  of 
the  cow  or  her  environment.  It  follows  that  the  scientific  injections 
give  nearly  accurate  results  as  to  the  frequency  with  which  tuber- 
culous cows  pass  tubercle  bacilli  with  their  milk;  but  they  give  no 
data  at  all  as  to  the  frequency  with  which  milk  from  tuberculous 
cows,  or  healthy  cows  in  a  tuberculous  environment,  contains  in- 
fectious material  when  it  is  drawn  and  handled  with  the  ordinary 
precautions  that  a  dairyman  can  economically  practice. 

The  observations  made  by  the  writers  definitely  show  that  the 
frequency  with  which  milk  contains  tubercle  bacilli  is  greatly  under- 
estimated, especially  when  it  is  milked  in  the  customary  way  from 
tuberculous  cows  with  healthy  udders,  or  from  entirely  healthy  cows 
in  a  tuberculous  environment. 

9.  It  has  been  positively  shown  that  the  introduction  of  a  small 
quantity  of  feces  from  tuberculous  cattle  into  normal  milk  is  equiva- 
lent to  the  introduction  of  a  sufficient  amount  of  infectious  material 
to  cause  a  generalized  tuberculosis  in  guinea  pigs  that  are  given  intra- 
abdominal injections  of  small  amounts  of  such  soiled  milk.     This 


1>4  i.w.,1  |    i  ROM     i  i  MOM  i  i ."i  -   ■   Mill. 

I-  Hi  If  BOi  "ii  I  \    Willi  I  lie   free-  Of  a   -e\erel\    a  lie.  ted  cow.  like   No.    1  1 :'., 

i  ooa  that  i-  swallowing  cultures  of  toberck  bacilli,  like  No.  B4, 
l>nt  also  with  the  recee  of  cowe  that  in  not  iowwa  to  be  aflecead  \\  ii  l> 
tubarculoaii  until  a  tuberculin  teat  or  poet-mortem  examination  baa 
been  Bade,  ea  bows  No-,  l  end  ■'<~'-i. 

The  quantity  of  feces  introduced  into  the  milk  waa  ao  greater  than 
frequently  entem  with  ordinary  milking. 

io.  We  era  unacquainted  with  any  meann  by  which  it  can  be  de 

terminec]  when  cattle  nr  their  feces  heroine  dan^'I'OUS  to  the  health 
q|  ptfftOM  Of  animal-;   hence  every  row    known  to  be  effected    with 

tuberovlosia  must  be  regarded  ea  positively  dangerous.  Phyaica]  eeo 
dition  gives  do  infonnatioo  from  which  it  i-  possible  to  determine 
how  seriously  i  cow  is  effected  with  tuberculoeia  or  how  freely  ehe  ii 
Bcattering  tubercle  bacilli  Cattle  effected  with  advanced  tnbcfcnlo* 
-i-  from  which  infection  is  being  disseminated  in  a  dangerous,  way 
may  retain  the  appearance  and  give  the  general  impreeaton  of  pet 
fed  health.  Frequently  nothing  abnormal  can  be  detected  snoot  them 
after  the  most  searching  examination  by  the  owner  or  even  by  i 

trained  veterinarian  J  and  besides  it   i-  not   ni-tomary  to  make  .  , 
fill  examination^  or  to  employ  professional  men  to  do  so  until  cattle 

-how  marked  symptoms  of  disease. 

11.  In  order  to  guard  against  the  spread  of  tuberculoaia  anions  cut- 
tle and  other  animals,  and  more  especially  for  the  protection  of  per 
sons,  every  dairy  cow  should  lx>  periodically  tested  with  tuberculin, 
and  every  cow  that  shows'  i  reaction  indicating  that  ahe  i-  affected 
with  tuberculoeia  should  at  once,  regardless  of  her  general  appearance 

or  condition  or  seinhlance  of  health,  be  removed  from  n-c  a-  I  dairy 

cow  and  from  all  contact  with  dairy  cattle  or  other  healthy  animal-. 

If  segregation  is  practiced,  it  should  l>c  complete,  bo  that  no  healthy 
animal  will  be  exposed  to  \'ri-i>-  that  may  -warm  with  living,  virulent 
tubercle  bacilli.' 

O 


A     001083  196 


